don't put extension params in 'CreateOpts' if unset; working rackspace acceptance test
diff --git a/rackspace/compute/v2/bootfromvolume/delegate.go b/rackspace/compute/v2/bootfromvolume/delegate.go
new file mode 100644
index 0000000..636ced6
--- /dev/null
+++ b/rackspace/compute/v2/bootfromvolume/delegate.go
@@ -0,0 +1,12 @@
+package bootfromvolume
+
+import (
+  "github.com/rackspace/gophercloud"
+  osBFV "github.com/rackspace/gophercloud/openstack/compute/v2/extensions/bootfromvolume"
+  osServers "github.com/rackspace/gophercloud/openstack/compute/v2/servers"
+)
+
+// Create requests the creation of a server from the given block device mapping.
+func Create(client *gophercloud.ServiceClient, opts osServers.CreateOptsBuilder) osBFV.CreateResult {
+  return osBFV.Create(client, opts)
+}